Tax dollars from 2012 are more than enough to cover arena construction loan.

Allentown's one-of-a-kind Neighborhood Improvement Zone captured $30.9 million in 2012 state tax payments that can be used for arena construction and downtown redevelopment this year.

It's the zone's first full-year tally, certified Friday by the Pennsylvania Department of Revenue, and evidence that the NIZ is already stoking economic activity downtown.

The zone's take for the last six months of 2011 was just $7.1 million in state taxes.

But it's unclear if the Allentown Neighborhood Improvement Zone Development Authority will be able to make good on its goal of returning $22 million to the state at the end of the year. That's the amount of state revenue businesses in the zone were estimated to be producing for Pennsylvania before the NIZ was created.

The authority faces a $6.5 million construction loan payment in 2012, a $5 million reserve fund deposit and must set aside an unknown portion of the proceeds for developers such as City Center Investment Corp., whose tenants produced some of the state tax revenues.

"What it shows at this point is the ability of the authority through the certification process to meet its debt obligations," said state Sen. Pat Browne, R-Lehigh, whose legislation created the zone. "There needs to be an official reconciliation and allocation over the next several months to determine the amount to be returned to the state."

The growth in NIZ tax revenue is encouraging and demonstrates the economic growth the zone is already producing, said Seymour Traub, chairman of the Neighborhood Improvement Zone Development Authority. But he admitted it may be tough to return the full $22 million this year.

"As the arena continues to be constructed and activity ramps up in the arena and other areas, the numbers will increase," Browne said.

Construction is under way on a $272 million arena complex at Seventh and Hamilton streets that will be home to the minor league Lehigh Valley Phantoms hockey team, an eight-story office tower housing a Lehigh Valley Health Network sports medicine center and a 200-room hotel.

State lawmakers created the zone in 2009, passing legislation written by Browne that allowed Allentown to draw a 127-acre district in which businesses' state and local taxes would be set aside to fund arena construction.

In addition, businesses such as City Center Investment that build or redevelop buildings within the zone's boundaries are able to redirect their tenants' state and city taxes to subsidize their own construction loans.

The zone took effect in July 2011, providing the authority with $7.1 million over the last six months of that year that was used to cover debt payments on a short-term arena construction loan in 2012. No leftover money was returned to the state in January 2013, resulting in a net loss of $7 million to state coffers.

The Allentown Neighborhood Improvement Zone Development Authority passed a resolution last month promising to make a good-faith effort to prioritize the return of unused revenue to the state at the end of each year in the future.

At the meeting, ANIZDA solicitor Jerome Frank said $22 million represents a solid estimate of what the businesses in the zone were generating in state taxes before the additional business activity created by the NIZ. If the authority can return at least that much at the end of each year, it would mean the zone has not hurt state revenues.

If the authority can't make its $22 million goal, it would mean the zone would be a drag on state revenues for a second year, although Browne said there may be some research done this year to determine whether $22 million is an accurate reflection of pre-NIZ revenues.

In the Lehigh Valley on Thursday, Pennsylvania Revenue Secretary Daniel Meuser said the state is working with the arena authority on how to make the annual amount of taxes returned to the state from the NIZ more predictable going forward.

"We can't budget if it's not definitive," he said.

While the bulk of the revenue diverted by the zone comes from the state, some $1 million in 2012 earned income and other local revenue generated within the zone — money that would have gone to the city and Allentown School District — will also be deposited with ANIZDA.

At the end of the year, leftover funds will be returned to the state, school district and city on a pro-rated basis.